Purring in the mild winter day, a small armada of S.U.V.s was parked Thursday morning along 42nd Street outside the New York Public Library. Inside was Mayor Bill de Blasio, at an interfaith prayer breakfast that went on for quite a while.

By divine right of mayoralty, or someone, 13 vehicles waited at the curb in a no-standing zone, among them four black S.U.V.s (three Chevy Suburbans and one Yukon XL) an ambulance, a huge E.M.S. vehicle and a police school safety van. The engines on those big boys were running while the mayor was inside, for about two hours.

At least one of the S.U.V.s had Taxi and Limousine Commission plates. It may not have been part of the official mayoral entourage, but its dashboard was anointed with the holiest of government oils: a police placard giving it license to park where unblessed mortals cannot.

One day earlier, Mr. de Blasio announced that the city would sue five big oil companies for the hardships and costs inflicted on New York by climate change. For an archipelago city with 520 miles of coastline, rising seas are no joke. Among the targets of the suits was Exxon Mobil, whose own scientists found, as most scientists have, that climate change was real and that human behavior was contributing to it. Even so, Exxon supported organizations that attacked those very conclusions. In the suit, New York follows the lead of governments around the Bay Area in California that have filed similar cases.

Whatever the merits of the suit, Mr. de Blasio and his predecessor, Michael R. Bloomberg, are the very embodiment of a possible line of defense by the oil companies. Namely, that it wasn’t the oil companies that created the greenhouse gases, but society in general — companies and individuals who used oil to generate electricity, or for transportation.

The reason for the trip? Mr. Bloomberg was speaking at a conference on climate change.

In New York, the police regard S.U.V.s as the most prudent for moving and protecting the mayor, and no one should begrudge any officials the security they need to carry out the work they do on behalf of the public. That goes for their recreation, at least for mayors, who put in long hours. At some point, every last one of them winds up splutteringly frayed or fried, so getting to a favorite gym probably helps keep Mr. de Blasio from losing his mind.

Mr. de Blasio has made populism work for him politically, but apparently too much righteous posturing can be a strain on the middle-aged back. Within a five-minute walk of the 42nd Street Library are 13 subway lines that fan out to virtually every corner of the city. Still, Mayor de Blasio hopped into one of the S.U.V.s leaving the library — a relatively efficient hybrid model, his spokesman pointed out. “The mayor uses public transit as much as his schedule allows, and we’re always looking to use it more,” Eric Phillips, the spokesman, said.

When was the last time?

December 11, Mr. Phillips said.

In the afternoon, WBUR aired an interview with the mayor by Meghna Chakrabarti about Mr. de Blasio’s climate actions, which, besides the lawsuit, include a proposal to divest the city’s pension investments in fossil fuel companies. These weren’t political stunts, the mayor said, arguing that the lawsuit was akin to suits against tobacco companies.

Wouldn’t it be better to keep stocks in those companies and have a voice in changing them, the host asked.

“I think you have to vote with your feet sometimes,” Mr. de Blasio replied.